Finger operated switch for controlling a surgical handpiece

ABSTRACT

According to the invention, a finger-operated switch for activating and operating an ultrasonic surgical handpiece is provided. The power output of the surgical handpiece is responsive and proportional to the pressure applied to the finger-operated switch. The finger-operated switch includes, but not limited to, force sensitive resistors whose resistance is proportional to the force applied by the finger of the human operator of the surgical handpiece, force sensitive capacitors whose capacitance is proportional to the pressure, deflection or compression of the insulation layer between two electrodes or is proportional to the spacing between the two conductive layers, strain gauges mounted underneath or integral to the housing of the surgical handpiece such that the pressure applied thereto results in an output change in the strain gauges, magnets or ferromagnets encased or embedded in an elastomer with a sensor inside the surgical handpiece that detects the field strength of the magnet and monitors changes relative to the force applied to the handpiece housing, and piezo film or piezo ceramic whose charge or voltage is proportional to the force applied.

RELATED APPLICATIONS

[0001] The present application relates to, and claims priority of, U.S.Provisional Patent Application Ser. No. 60/242,159 filed on Oct. 20,2000 and commonly assigned to the same assignee as the presentapplication, having the title FINGER OPERATED SWITCH FOR CONTROLLING ASURGICAL HANDPIECE, which is incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The invention generally relates to the field of medical orsurgical instruments and, more particularly, to a novel finger-operatedswitch for controlling a medical or surgical handpiece.

DESCRIPTION OF THE RELATED ART

[0003] Ultrasonic medical or surgical instruments have gained widespreadacceptance in the microsurgical field for use in the fragmentation andremoval of body tissue. A typical ultrasonic instrument includes anultrasonic transducer housed in a handpiece. The ultrasonic transduceris operable for converting electrical energy supplied thereto intohigh-velocity vibrational movements. The transducer-generated ultrasonicvibrations are transmitted to a surgically operative tip (such as ablade or a coagulator) that is coupled thereto.

[0004] U.S. Pat. No. 5,026,387 issued to Thomas (the '387 patent),assigned to the assignee of the present application and incorporatedherein by reference, describes such an ultrasonic surgical instrument.The ultrasonic instrument according to the '387 patent includes a “poweron demand” control feature for causing a surgically sharp cuttinginstrument, such as a scalpel blade or other surgical instrument (e.g. adull cautery blade) to automatically shift its operation between anunloaded or idle state and a loaded or cutting state, and vice versa,depending on whether the instrument is in contact with a bodily tissue.

[0005]FIG. 1 is a diagram illustrating a typical ultrasonic instrumentknown in the art in accordance with the '387 patent. As generally shownin FIG. 1, a harmonic generator 1 provides electrical energy to thehandpiece 2 which imparts ultrasonic longitudinal movement to a surgicaldevice, such as a sharp scalpel blade 3 which is used for dissectionand/or coagulation. The harmonic generator 1 includes a liquid crystaldisplay device 4 indicating, e.g., the selected cutting power level as apercentage of the maximum available cutting power. The power selectionlevel as well as other functions, such as coagulation mode duration, mayalso be selected by pushing buttons 5 in response to a menu appearing onthe display 4. The handpiece 2 is connected to the harmonic generator 1by a coaxial cable 8. As illustrated in more detail in FIG. 1a and the'387 patent, the ultrasonic handpiece 2 houses an ultrasonic system forconverting electrical energy to mechanical energy that results inlongitudinal vibrational motion. The ultrasonic system comprises atransducer 9, a mounting device 10 and a surgical device 11 such as thescalpel blade and holder. The transducer 9 includes a stack of ceramicpiezoelectric elements 12 with a motionless node at the center of thestack sandwiched between two aluminum cylinders 13 and 14. Thetransducer 9 is fixed to the mounting device 10 in a permanent manner.In turn, the mounting device 10 is attached to the housing at anothermotionless node by an integral ring 15. The mounting device 10,transducer 9 and the surgical device 11 are designed and fabricated tooscillate at the same resonant frequency, with each element tunedaccordingly such that the resulting length of each such element isone-half wavelength. Expansion of the piezoelectric ceramic elements 12results in the initiation of motion in the acoustic system of thetransducer 9.

[0006] Detachably connected to the harmonic generator 1 is a foot switch6 for causing activation of the device in a coagulation operation mode.A switch 6 a is incorporated in the handpiece 2. However, the switch 6 aas found in the art includes shortcomings such as a high risk ofinadvertent activation and deactivation. Long-term operation results infatigue in the finger of the human operator of the handpiece 2.

[0007] Therefore, there is a general need in the art for an improvedswitch for use with an ultrasonic surgical handpiece. In particular, aneed exists for a switch in an ultrasonic surgical handpiece that iseasy-to-operate, reduces the risk of inadvertentactivation/deactivation, and reduces fatigue in the finger of the humanoperator.

SUMMARY OF THE INVENTION

[0008] According to the invention, a finger-operated switch foractivating and operating an ultrasonic surgical handpiece is provided.The power output of the surgical handpiece is responsive andproportional (linearly, nonlinearly proportional or in terms of a stepfunction) to the pressure applied to the finger-operated switch. Thefinger-operated switch may include, but is not limited to: (1)electromechanical switches; (2) force sensitive resistors whoseresistance is proportional to the force applied by the finger of thehuman operator of the surgical handpiece; (3) force sensitive capacitorswhose capacitance is proportional to the pressure, deflection orcompression of the insulation layer between two electrodes or isproportional to the spacing between the two conductive layers; (4)strain gauges mounted underneath or integral to the housing of thesurgical handpiece such that the pressure applied thereto results in anoutput change in the strain gauges; (5) magnets or ferromagnets encasedor embedded in an elastomer with a sensor inside the surgical handpiecethat detects the field strength of the magnet and monitors changesrelative to the force applied to the handpiece housing; and (6) piezofilm or piezo ceramic material whose charge or voltage is proportionalto the force applied.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] These and other features, aspects, and advantages of theinvention will become more readily apparent with reference to thefollowing detailed description of a presently preferred, but nonethelessillustrative, embodiment when read in conjunction with the accompanyingdrawings. The drawings referred to herein will be understood as notbeing drawn to scale, except if specifically noted, the emphasis insteadbeing placed upon illustrating the principles of the invention. In theaccompanying drawings:

[0010]FIG. 1 is a diagram illustrating an ultrasonic surgical systemknown in the art;

[0011]FIG. 1a is a diagram illustrating the interior of the ultrasonicsurgical handpiece of the surgical system shown in FIG. 1 and known inthe art;

[0012]FIG. 2 is an illustration of a generator console for an ultrasonicsurgical cutting and hemostasis system according to the invention;

[0013]FIG. 2a is a schematic view of a cross section through theultrasonic scalpel handpiece of the system of FIG. 2;

[0014]FIG. 2b is longitudinal cross-sectional view of an exemplarybutton switch according to the invention;

[0015]FIG. 3a is a diagram illustrating a housing deflection embodimentof the switch for controlling the ultrasonic surgical handpieceaccording to the invention;

[0016]FIG. 3b is a diagram illustrating a pressure button embodiment ofthe switch for controlling the ultrasonic surgical handpiece accordingto the invention;

[0017]FIGS. 3c, 3 d, 3 e and 3 f are diagrams illustrating variousmagnet button embodiments of the switch for controlling the ultrasonicsurgical handpiece according to the invention;

[0018]FIGS. 4a and 4 b are diagrams illustrating the various powerlevels of operation for the ultrasonic surgical handpiece controlled bythe switch according to the invention;

[0019]FIG. 5 is a flow diagram generally illustrating the methodaccording to the invention for controlling the ultrasonic surgicalhandpiece using a switch;

[0020]FIGS. 6, 6b and 6 c are diagrams illustrating a ring embodiment(and cross-sectional views thereof) for the switch for the surgicalhandpiece according to the invention;

[0021]FIGS. 7a through 7 i are diagrams showing partial cross sectionalviews of various embodiments of the ring switch for the ultrasonicsurgical handpiece according to the invention; and

[0022]FIGS. 8a, 9, 9 a, 10, 10 a, 10 b, 11 and 12 are diagramsillustrating various embodiments for the ring switch with activationzones for the ultrasonic surgical handpiece according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023]FIG. 2 is an illustration of a system for implementing surgicalprocedures according to the invention. By means of a first set of wiresin cable 526, electrical energy, i.e., drive current, is sent from thegenerator console 510 to a handpiece 530 where it imparts ultrasoniclongitudinal movement to a surgical device or end effect or, such as asharp scalpel blade 532. This blade can be used for simultaneousdissection and cauterization of tissue. The supply of ultrasonic currentto the handpiece 530 may be under the control of a distally locatedswitch 534 located on the handpiece, which is connected to the generatorin console 510 via wires in cable 526. The generator may also becontrolled by a foot switch 540, which is connected to the console 510by another cable 550. Thus, in use a surgeon may apply an ultrasonicelectrical signal to the hand piece, causing the blade to vibratelongitudinally at an ultrasonic frequency, by operating the switch 534on the handpiece with his finger, or by operating the foot switch 540with his foot.

[0024] The generator console 510 includes a liquid crystal displaydevice 512, which can be used for indicating the selected cutting powerlevel in various means such, as percentage of maximum cutting power ornumerical power levels associated with cutting power. The liquid crystaldisplay device 512 can also be utilized to display other parameters ofthe system. Power switch 511 is used to turn on the unit. While it iswarming up, the “standby” light 513 is illuminated. When it is ready foroperation, the “ready” indicator 514 is illuminated and the standbylight goes out. If the unit is to supply maximum power, the MAX button515 is depressed. If a lesser power is desired, the MIN button 517 isactivated. This automatically deactivates the MAX button. The level ofpower when MIN is active is set by button 516.

[0025] When power is applied to the ultrasonic hand piece by operationof either switch 534 or 540, the assembly will cause the end effector(surgical scalpel or blade) to vibrate longitudinally at approximately55.5 kHz (or about 25 kHz in another embodiment), and the amount oflongitudinal movement will vary proportionately with the amount ofdriving power (current) applied, as adjustably selected by the user.When relatively high cutting power is applied, the blade is designed tomove longitudinally in the range of about 40 to 100 microns at theultrasonic vibrational rate. Such ultrasonic vibration of the blade willgenerate heat as the blade contacts tissue, i.e., the acceleration ofthe blade through the tissue converts the mechanical energy of themoving blade to thermal energy in a very narrow and localized area. Thislocalized heat creates a narrow zone of coagulation, which will reduceor eliminate bleeding in small vessels, such as those less than onemillimeter in diameter. The cutting efficiency of the blade, as well asthe degree of hemostasis, will vary with the level of driving powerapplied, the cutting rate of the surgeon, the nature of the tissue typeand the vascularity of the tissue.

[0026] As illustrated in more detail in FIG. 2a, the ultrasonichandpiece 530 houses a piezoelectric transducer 536 for convertingelectrical energy to mechanical energy that results in longitudinalvibrational motion of the ends of the transducer. The transducer 536 isin the form of a stack of ceramic piezoelectric elements with a motionnull point located at some point along the stack. The transducer stackis mounted between two cylinders 531 and 533. In addition a cylinder 535is attached to cylinder 533, which in turn is mounted to the housing atanother motion null point 537. A horn 538 is also attached to the nullpoint on one side and to a coupler 539 on the other side. Blade 532 isfixed to the coupler 539. As a result, the blade 532 will vibrate in thelongitudinal direction at an ultrasonic frequency rate with thetransducer 536. The ends of the transducer achieve maximum motion with aportion of the stack constituting a motionless node, when the transduceris driven with maximum current at the transducers' resonant frequency.However, the current providing the maximum motion will vary with eachhand piece and is a value stored in the non-volatile memory of the handpiece so the system can use it.

[0027] The parts of the handpiece are designed such that the combinationwill oscillate at the same resonant frequency. In particular, theelements are tuned such that the resulting length of each such elementis one-half wavelength. Longitudinal back and forth motion is amplifiedas the diameter closer to the blade 532 of the acoustical mounting horn538 decreases. Thus, the horn 538 as well as the blade/coupler areshaped and dimensioned so as to amplify blade motion and provideharmonic vibration in resonance with the rest of the acoustic system,which produces the maximum back and forth motion of the end of theacoustical mounting horn 538 close to the blade 532. A motion from 20 to25 microns at the transducer stack is amplified by the horn 538 intoblade movement of about 40 to 100 microns.

[0028]FIG. 2b is a more detailed longitudinal cross-sectional view of anexemplary button switch according to the invention. This design, as wellas others disclosed herein, allows for operation of the hand pieces invarious modes, and is also described in related U.S. patent applicationSer. No. 09/693,549, commonly assigned to the same assignee as thepresent application, having the title RING CONTACT FOR ROTATABLECONNECTION OF SWITCH ASSEMBLY FOR USE IN AN ULTRASONIC SURGICAL SYSTEMand filed on Oct. 20, 2000, which is incorporated herein by reference.The switch for use with an ultrasonic surgical handpiece according tothe invention includes two independent switches under generally the sameelastomer or flexible thin metallic skin with a middle recess forresting a finger of a human operator. The middle recess serves as atactile reference point, as the blade and handpiece arenon-symmetrically configured, for the human operator which avoidsinadvertent activation or deactivation. In addition, the middle recessprovides a safe, convenient spot for the human operator to grasp thehandpiece and the switch without inadvertently activating the switch.The switch is also ergonomically designed and tested to be comfortablygrasping for small or big hands of any human operator of the handpiece.

[0029] Referring to FIG. 2b, the ultrasonic surgical handpiece accordingto the invention provides a switch that includes a pair of switch buttonmembers 270, detachably secured within the button sections 214, whichare about 180° apart to permit convenient grasping of the handpiece yetavoid inadvertent activation or deactivation. Each switch button member270 has an upper surface 272 and an opposing lower surface 274 with thelower surface 274 seating against the outer shell 201. First and secondposts 276, 278, respectively, extend outwardly away from the lowersurface 274 of the switch button member 270. The first and second posts276, 278 are spaced apart from one another with a center traverse wallbeing formed therebetween. The upper surface 272 includes a first raisedsection 282 and a second raised section 284 spaced therefrom with acenter recessed section 286 being formed therebetween. The upper surface272 is thus slightly beveled as the switch button member 270 transitionsfrom the center recessed section 286 to the first and second raisedsections 282, 284. In the illustrated embodiment, the first post 276 isdisposed generally below the first raised section 282 and the secondpost 278 is disposed generally below the second raised section 284 sothat when a user presses downwardly upon the first raised section 282,the first post 276 is also directed downward. Similarly, when the switchis pressed downwardly upon the second raised section 284, the secondpost 278 is directed downward. In another embodiment according to theinvention, the switch is a dome switch which includes a dome of a thinmetallic skin that collapses downward as pressure is applied thereto.

[0030] The switch button members 270 are designed to act as adepressable switch button for selectively causing activation of theultrasonic surgical handpiece according to the invention. The switchbutton members 270 are formed of suitable materials, such as plasticmaterials, and preferably the switch button members 270 are formed of aresilient plastic material. In one exemplary embodiment, the switchbutton members 270 are formed of silicon which permits the members to besufficiently resilient enough so that they may be fitted and securedwithin the button sections 214 to seal internally and also provide anengagement surface for a finger or thumb of a human operator duringoperation of the handpiece. In one aspect of the present invention, thecontour of the switch button member 270 permits a fingertip of a humanoperator to easily rest between the first and second raised sections 282and 284. In other words, the finger tip or thumb of a human operatorseats and rests within the center recessed section 286 without actuatingthe switch mechanism. The switch button members 270 are disposed withinthe button sections 214. The switch button members 270 are spaced about180° from one another. A pair of fasteners 300 are positioned beneaththe center traverse wall. Each button section 214 formed in the outershell 201 contains openings formed therein and spaced apart from oneanother for receiving the first and second posts 276 and 278 of theswitch button member 270. The exemplary switch mechanism is anelectromechanical switch that is depressable for activation and,according to the present invention, two switch button members 270 form,at least in part, the switch. Each switch button member 270 has twoswitch sites. For example, the first raised section 282 and the firstpost 276 are associated with a first switch site and the second raisedsection 284 and the second post 278 are associated with a second switchsite. Preferably, the first switch site of one switch button member 270is generally the same as the first switch setting of the other switchbutton member 270 disposed about 180° therefrom. In one exemplaryembodiment, the first switch site is a maximum power setting (MAX) andthe second switch setting is an intermediate power setting which caninclude a minimum (MIN). It will be understood that the opposite mayequally be true, in that the first switch setting may be designed forcausing the transmission of intermediate power to the handpieceaccording to the invention and the second switch setting will then causethe transmission of maximum power to the handpiece.

[0031] Distally placing the switch on the handpiece according to theinvention provides significant advantages over the prior art. Asswitches in the art are placed on the non-distal end (e.g., medial orproximal end) of the handpiece, blade control becomes ineffective sinceoperating the blade with a switch proximally positioned on the handpiececreates substantially uncontrollable jitter when using the blade forcutting or coagulation on a tissue. Pressing the switches proximallylocated on the handpiece has negative effects and disrupts bladepositioning on the tissue. Such is particularly inconvenient forperforming surgery and burdensome for a human operator in controllingthe handpiece. Positioning the switches on the distal end of thehandpiece significantly reduces the occurrence of blade jitter andgenerally improves operational control of the handpiece by the humanoperator.

[0032] The switch according to the invention is configured on the distalend of the handpiece, to permit accurate blade control, handpiecehandling and to conveniently operate the switches without jitter of theblade, with the scalpel blade 532 which is screwed onto the handpieceand rotatable. The switch according to the invention, in relation withthe blade 532, is configured so that the switch is generally aligned bya human operator with the blade as it is rotated or indexed to aparticular blade symmetry. The alignment by the human operator (or useralignment) can be incremental (using indents or detents), continuous orindexed to particular symmetries. The switch can also be generallyaligned with the rotating blade with a particular symmetry, depending onthe configuration of the handpiece and needs of the human operator forcutting or coagulation. Other embodiments of the switch according to theinvention include a switch with a single button member, metal domeswitches whose dome collapses for contacting a circuitry on a printedcircuit board (PCB), which is described in related U.S. patentapplication Ser. No. 09/693,549, commonly assigned to the same assigneeas the present application, having the title RING CONTACT FOR ROTATABLECONNECTION OF SWITCH ASSEMBLY FOR USE IN AN ULTRASONIC SURGICAL SYSTEMand filed on Oct. 20, 2000.

[0033] The switch according to the invention can also be used forcontrolling functions in the generator console 510 including initiatingdiagnostic functions on the handpiece, and implementing a standby mode.In a particular embodiment according to the invention, the standby modeof operating the handpiece, which renders the switch inoperable, isactivated by applying pressure to both buttons of the switch atgenerally the same time.

[0034] The standby mode is subsequently deactivated by doing the same,i.e., by applying pressure to both buttons of the switch at generallythe same time.

[0035]FIG. 3a is a cross-sectional view (taken at A-A of FIG. 2) thatillustrates a housing deflection embodiment of the switch for anultrasonic surgical handpiece according to the invention. This one-pushbutton design, as well as others disclosed herein, allows for operationof the hand pieces in various modes. The switch according to the housingdeflection embodiment as shown in FIG. 3a includes a pressure sensor 31mounted inside the housing 33 of the ultrasonic handpiece 32 where it isrelatively protected from the environment. The sensor 31, located on theinternal side of a thin wall area 36 of the handpiece housing 33,detects pressure 30 applied by a finger of a human operator of thehandpiece 32. The sensor 31 can be, but is not limited to, anelectro-mechanical switch, a strain gauge, a pressure sensitiveresistor/sensor combination, a hall affect device/magnet combination,reed switch/magnet combination, a piezo element, or a capacitance sensorwhich detects the force applied to the thin wall area 36. As fingerpressure 30 is applied to the thin wall 36, the portion of the handpiecehousing 33 at the thin wall 36 deflects, which is detected by the sensor31. The sensor 31 outputs a response signal to the handpiece. Thissignal is conveyed through cable 526 to a detection circuit in thegenerator console 510 that controls the application of power to thetransducers in the handpiece in response thereto.

[0036] The switch according to the invention provides multi-levelactivation and operation via the thin wall area 36, where various levelsof applied pressure determine the mode of operation for the handpiece32. In accordance with the magnitude of the finger pressure 30, theoutput from the sensor 31 causes the handpiece 32 to be “on” or “off” ormore particularly, operating with a power level proportional to thefinger pressure 30 as applied to the thin wall 36. For example, afterinitial activation of the handpiece 32 (“on”), a very low appliedpressure 30 enables low power level operation of the handpiece 32. Asomewhat higher applied pressure 30 enables higher power level operationof the handpiece 32, without excessive finger pressure fatigue for thehuman operator of the handpiece 32.

[0037]FIG. 3b is a cross-sectional view (taken at A-A of FIG. 2) thatillustrates a pressure button embodiment of the switch for an ultrasonicsurgical handpiece according to the invention. According to the pressurebutton embodiment which is a one-push button design, the handpiece 32includes a button 37 mounted on a button support 38 on the exterior ofthe handpiece housing 33. A pressure sensor 34 is located inside thehandpiece housing 33 and is separated from the button 37 by a thin wallarea 36 of the handpiece housing 33. When finger pressure 30 is appliedto the button 37, the thin wall area 36 is deflected and a concentrated,focused pressure is detected by the pressure sensor 34. Thethumbnail-like design of the button having a pointy end 37A towards thepressure sensor 34 ensures transmission of concentrated pressure to thepressure sensor 34, which requires less effort by a human operatorduring application of pressure to the button 37. The pressure sensor 34detects the force applied to the thin wall area 36 and outputs aresponse signal to the handpiece 32 which transmits it to a detectioncircuit in the generator console 510. The switch according to theinvention provides multi-level activation and operation via the thinwall area 36, where various levels of applied pressure determine themode of operation for the handpiece 32. In accordance with the magnitudeof the finger pressure 30, the output from the sensor 31 causes thehandpiece 32 to be “on” or “off” or more particularly, operating with apower level proportional to the finger pressure 30 as applied.

[0038]FIG. 3c is a cross-sectional view (taken at A-A of FIG. 2) thatillustrates a magnet button embodiment of the switch for an ultrasonicsurgical handpiece 32 according to the invention. According to thisembodiment which is a one-push button design, the handpiece 32 includesan elastomeric pad 39 with a magnet 40 (or, ferromagnetic element,metallic element, or coil) embedded therein. A sensor 35 is locatedinside the handpiece housing 33 and detects the field strength of themagnet. Sensor 35 monitors changes in field strength related to theforce applied to the handpiece housing 33. The sensor 35 can be, but isnot limited to, a reed switch; a hall effect device; or an inductance,proximity, or capacitance sensor, which responds to the relativeposition of a neighboring piece of magnet or ferromagnet or material(e.g., magnet 40). As finger pressure 30 is applied to the elastomericpad 39, the magnet 40 moves closer to the sensor 35. The switchaccording to the invention provides multi-level activation andoperation, where various levels of applied pressure determine the modeof operation for the handpiece 32. Depending on the magnitude of thefinger pressure 30, the output from the sensor 35 causes the handpiece32 to be “on” or “off” or more particularly to operate with a powerlevel proportional to the finger pressure 30 applied.

[0039]FIG. 3d is a partial cross-sectional view (taken at A-A of FIG. 2)that illustrates another magnet button embodiment of the switch for anultrasonic surgical handpiece 32 according to the invention. FIG. 3d issimilar to FIG. 3c, except that it is greatly enlarged and the magnet 41is embedded in a slide button 48 as opposed to the elastomeric pad 39 ofFIG. 3c. According to this particular embodiment, the handpiece 32includes a slide button 48 slidably attached on the outside of thehandpiece housing 33 with a magnet 41 (or, ferromagnetic element,metallic element, or coil) embedded therein. A sensor 44 is locatedinside the handpiece housing 33 and detects the field strength of themagnet. In particular, sensor 44 monitors changes in the magnet's fieldstrength related to the force applied to the handpiece housing slidebutton. The sensor 44 can be, but is not limited to, a reed switch; ahall effect device; or an inductance, proximity, or capacitance sensor,which responds to the relative position of a neighboring piece, ofmagnet or ferromagnet (e.g., magnet 41). As finger pressure 30 isapplied to the slide button 48, the embedded magnet 41 moves closer tothe sensor 44. If desired, slide button 48 can be attached to a springwhich tends to restore it to its initial position. As a result, theposition of slide button 48 is proportional to the amount of forceapplied, and not just simply the application of some force, for a periodof time.

[0040] The switch according to the embodiment of FIG. 3d providesmulti-level activation and operation, where various levels of appliedpressure on the application of pressure for various periods determinethe mode of operation for the handpiece 32. Depending on the magnitudeof the finger pressure 30 or where the switch is when the pressure isreleased (assuming no spring return), the output from the sensor 44causes the handpiece 32 to be “on” or “off” or more particularly,operating with a power level proportional to the position or fingerpressure 30 as applied.

[0041]FIG. 3e is a partial cross sectional view (taken at A-A of FIG. 2)that illustrates another magnet button embodiment of the switch for anultrasonic surgical handpiece 32 according to the invention. FIG. 3e issimilar to FIG. 3d, except that the magnet 42 is embedded in a lever 49as opposed to the slide button 48 of FIG. 3d. According to thisparticular embodiment, the handpiece 32 has the lever 49 extending fromthe outside to the inside of the handpiece housing 33, with a magnet 42(or, ferromagnetic element, metallic element, or coil) embedded therein.The lever 49 is made of an elastic material and responds to fingerpressure 30 so as to be bendable to the left or right. Two sensors 45and 46 are located inside the handpiece housing 33 that detect the fieldstrength of the magnet and monitor changes therein relative to the forceapplied to the lever 49. The sensors 45 and 46 can be, but are notlimited to a reed switch; a hall effect device; or an inductance,proximity, or capacitance sensor which responds to the relative positionof a neighboring piece of magnet or ferromagnet (e.g., magnet 42) asplastic lever 49 is bent. As finger pressure 30 is applied to the lever49, the embedded magnet 42 moves closer to either sensor 45 or sensor46. The switch according to the invention thus provides multi-levelactivation and operation, where various levels of applied pressure andthe direction of that pressure on lever 49 determine the mode ofoperation for the handpiece 32. Depending on the magnitude and directionof the finger pressure 30, the output from the sensor 45 causes thehandpiece 32 to be “on” (if the lever 49 is pressed toward the sensor 45and against the handpiece housing 33 fully), or operating with a powerlevel proportional to the finger pressure 30 as applied. Similarly,depending on the magnitude of the finger pressure 30, the output fromthe sensor 46 causes the handpiece 32 to be “off” (if the lever 49 ispressed toward the sensor 46 and against the handpiece housing 33fully), or operating with a power level proportional to the fingerpressure 30 as applied.

[0042] As an alternative, if no pressure is applied and sensors 45, 46receive relatively equal field strengths, the handpiece can be off. Itcan then operate in one mode (e.g. cutting) as different levels, as thelever is pressed toward sensor 45 and in a different mode (e.g.coagulation) at different levels as the lever is pressed towards sensor46.

[0043]FIG. 3f is a cross sectional view (taken at A-A of FIG. 2) thatillustrates another magnet button embodiment of the switch for anultrasonic surgical handpiece 32 according to the invention. FIG. 3f issimilar to FIG. 3c, except that the magnet 43 is embedded in an elasticring 50 as opposed to the elastomeric pad 39 of FIG. 3c. A sensor 47 islocated inside the handpiece housing 33 that detects the field strengthof the magnet 43 and monitors changes in the field strength relative tothe force applied to the ring 50 toward the housing 33. The sensor 47can be, but is not limited to a reed switch; a hall effect device; or aninductance, proximity, or capacitance sensor which responds to therelative position of a neighboring piece of magnet or ferromagnet (e.g.,magnet 43). As finger pressure is applied to the ring 50, the embeddedmagnet 43 moves closer to the sensor 47. The switch according to theinvention provides multi-level activation and operation, where variouslevels of applied pressure on the elastic ring 50 determine the mode ofoperation for the handpiece 32. Depending on the magnitude of the fingerpressure, the output from the sensor 47 causes the handpiece 32 to be“on” or “off” or more particularly, operating with a power levelproportional to the finger pressure as applied.

[0044] The switch according to the invention, as described herein andshown in the accompanying figures, provides multi-level activation andoperation at different power levels, where various levels of appliedpressure determine the mode of operation for the ultrasonic surgicalhandpiece. FIG. 4A is a diagram that illustrates the operation of asingle power level embodiment of the ultrasonic surgical handpiecehaving a switch according to the invention. The relationship of fingerpressure applied to the switch and the power level of the ultrasonicsurgical handpiece referenced by time is shown. A high finger pressureis required to activate the handpiece at time t0. Once activated, thehandpiece operates at power level 1. Thereafter, only a sufficientlyhigh finger pressure (higher than the “low” finger pressure as marked)is needed to keep the handpiece operative at power level 1. Once thefinger pressure applied to the switch equals or falls below the “low”threshold at time t1, the handpiece turns “off” and ceases to receiveoutput power.

[0045]FIG. 4b is a diagram that illustrates the operation of a dualpower level embodiment of the ultrasonic surgical handpiece having aswitch according to the invention. The relationship of finger pressureapplied to the switch and the power level of the ultrasonic surgicalhandpiece referenced by time is shown. A high finger pressure isrequired to activate the handpiece at time t0. Once activated, thehandpiece operates at power level 1. Once the finger pressure applied tothe switch equals or falls below the “medium” threshold at time t1, thehandpiece operates at power level 2. Thereafter, if the finger pressureequals to or falls below the “low” threshold at time t2, the handpieceturns “off” and ceases to receive output power.

[0046]FIGS. 4a and 4 b merely illustrate two embodiments, i.e., thesingle power level and the dual power level embodiments, respectively,of the multi-level power operation for the ultrasonic surgical handpiecehaving a pressure sensitive switch according to the invention. Othermulti-level embodiments, e.g., three-level, four-level, etc., are alsoconsidered to be within the scope and spirit of the present invention.

[0047] Accordingly, the invention provides a method for controlling anultrasonic surgical handpiece using a switch located on the housing ofthe handpiece, which comprises the steps of: (1) monitoring the pressureapplied to the housing a lever or ring compressors the switch; (2)activating the surgical handpiece at a high power level if the monitoredpressure reaches a high threshold; (3) operating the surgical handpieceat a corresponding intermediate power level if the monitored pressurereaches a specific intermediate threshold below the high threshold; and(4) deactivating the surgical handpiece if the monitored pressure isbelow a low threshold which is less than the specific intermediatethreshold. The finger-operated switch includes, but is not limited to,(a) an electromechanical switch, (b) force sensitive resistors whoseresistance is proportional to the force applied by the finger of thehuman operator of the surgical handpiece; (c) force sensitive capacitorswhose capacitance is proportional to the pressure, deflection orcompression of the insulation layer between two electrodes or isproportional to the spacing between the two conductive layers; (d)strain gauges mounted underneath or integral with the housing of thesurgical handpiece such that the pressure applied thereto results in anoutput change in the strain gauges; (e) magnets or ferromagnets encasedor embedded in an elastomer with a sensor inside the surgical handpiecethat detects the field strength of the magnet and monitors changesrelative to the force applied to the handpiece housing; and (f) piezofilm or piezo ceramic materials whose charge or voltage is proportionalto the force applied.

[0048]FIG. 5 is a flow diagram that illustrates the method according tothe invention for controlling the ultrasonic surgical handpiece using apressure-sensitive switch.

[0049] In step 51, the pressure applied to the housing of the surgicalhandpiece, elastomer material mounted on the housing, an elastic lever,or an elastic ring is monitored. The monitored pressure is testedagainst a high threshold (step 52). If the monitored pressured does notreach the high threshold, the control flow reverts to step 51 whichcontinues the monitoring of the pressure applied to the housing of thesurgical handpiece. If the monitored pressure reaches the highthreshold, the surgical handpiece is activated to operate at a firstpower level (step 53). If the surgical handpiece does not havemulti-level operational capability (step 54), then control flow goes tostep 57 and the monitored pressure is tested against a low threshold. Ifthe monitored pressure reaches the low threshold, then the surgicalhandpiece is deactivated (step 58). This operation could also be basedon a single threshold. In particular, if it is determined that thepressure has exceeded a minimum level, the power is turned on full andremains there until it is determined that the pressure has fallen belowthe single minimum threshold.

[0050] If the surgical handpiece can operate at multiple power levels(step 54), then in the method of FIG. 4, the monitored pressure istested against a plurality of specific thresholds (step 55). If themonitored pressure reaches a specific intermediate threshold, then thesurgical handpiece operates at a power level corresponding to thatspecific threshold (step 56). In step 57, if the monitored pressurereaches the low threshold, then the surgical handpiece is deactivated.If the monitored pressure has not yet reach the low threshold, thecontrol flow reverts back to step 55 and the surgical handpiececontinues to operate at multiple power levels.

[0051] When the system has multiple thresholds, it can step down from aminium various power levels as the pressure is released. Alternativelyit can turn on at a minimum level and step up to higher levels of poweras the pressure is increased.

[0052] In a further embodiment, the switch according to the inventionincludes a sensor that is flat and tape-like. This type of sensor ismade of piezo-electric material or a pressure-sensitive resistor (orresistor tape). Such a flat tape-like sensor provides a very low profilesensing means that is relatively easily mounted on or in a surgicalhandpiece. With the flat tape-like sensor, the switch is configured asan “active zone” on or around the surgical handpiece for activating andcontrolling the handpiece. The switch is activated when the surgeon'sfinger is on or applies pressure to the active zone.

[0053]FIG. 6 is a diagram that illustrates a ring embodiment for theswitch for the handpiece according to the invention. A harmonicgenerator 510, illustrated in FIG. 2, provides electrical energy to thehandpiece 62 which imparts ultrasonic longitudinal movement to asurgical device, such as a sharp scalpel blade 603 used for dissectionor coagulation. The handpiece 62 is connected to the harmonic generator510 by the coaxial cable 26X. The ring switch 60 a is a ring-likecircumferential appendage on the handpiece 62, located near the distalend thereof. The handpiece 62 is activated when pressured is applied,e.g, by a finger of a human operator of the handpiece 62, to the sidewall of the switch 60 a. The mode of activation (e.g., cutting orcoagulation) is determined by which side of the ring switch 60 a ispressed upon. Pressure may be applied in a direction that is notperpendicular to the handpiece 62 and still activate it. Pressureapplied to the top of the ring switch 60 a which is perpendicular to thehandpiece 62, depending on the particular embodiment, can lead to anumber of functions. That is, the pressure applied to the top of thering switch 60 a may be ignored on the one hand, invoke a third mode ofoperation other than cutting and coagulation, or default to one of thetwo selectable modes of operation. For example, when the ring switch 60a is pressed, the base of the ring switch 60 a applies pressure to oneof several pressure-sensitive sensors which can activate the handpiece62. One sensor 65 is activated when the ring switch 60 a is pushed fromone direction, another sensor 67 activated when the ring is pushed fromthe other direction, and both sensors are activated when the ring ispushed upon from the above with a pressure force perpendicular to thehandpiece 62.

[0054] The ring switch 60 a can be mounted directly or indirectly to asingle sensors 69 such that when one side of the ring is pressed, thesensor is pushed upon. Conversely, when the opposing side of the ring ispushed, the sensor is pulled upon, or any pre-biased pressure is therebyreduced. Electronic circuitry in the sensor or handpiece can detectwhether push or pull (or reduced pressure) is present and evoke acorresponding mode of operation in response.

[0055] In the alternative, the ring itself can be the sensor, where thering switch 60 a is made of a piezo material that, when pressedthereupon, generates a voltage proportional to the force applied and thedirection of that applied force. Pressing against one side of the ringgenerates one polarity signal and pressing against the other sidegenerates an opposite polarity signal, thereby permitting at least twomodes of operation from a single ring/sensor. Furthermore, the ringswitch 60 a can be non-piezo such as a force-sensitive resistor, yetmechanically coupled to a piezo ring which responds proportionally topressure applied to the ring and whose output polarity is dependent onwhich side of the ring is pressed.

[0056] The ring switch 60 a can also utilize a capacitance transducer,which comprises a relatively inflexible metal center ring 64 with anouter layer of foam or elastomer and a flexible metal ring electrode 66(FIG. 6a, which is a cross section along line B-B in FIG. 6; and FIG. 6ba cross section along line C-C in FIG. 6). When pressure is applied toone side of the ring, the pressure applied against the outer ring causesit to be deflected and thereby depress the foam or elastomer, whichbrings the outer ring closer to the center ring and thereby reduces thecapacitance in proportion to the pressure applied.

[0057] In a further embodiment, the switch 60 a can function as a switchdue to the hysteresis effect. Hysteresis is the lagging of an effectbehind its cause, as when the change in magnetism of a body lags behindchanges in the magnetic field. The switching functionality is achievedper the lagging or retardation of the hysteresis effect when thepressure applied or forces acting upon the switch 60 a are changed, andper the temporary resistance to change from a condition previouslyinduced in magnetism or thermolelectricity (e.g., on reversal ofpolarity).

[0058] The ring switch 60 a can also be one piece or segmented into twoor more pieces. Segmenting the ring substantially improves thelocalization of sensor activation and reduces potential mechanicalartifact activation of the sensor at ring locations distant to where thepressure is being applied. Segmentation also provides the ability todeactivate or reduce the sensitivity of selected segments for theconvenience of the end user of the handpiece 62.

[0059] In addition, the ring switch 60 a serves as a convenientreference point that provides visual tactile feedback of where to applypressure for activating the handpiece 62. The ring switch 60 a can alsobe used to indicate activation status. For example, the ring can betransparent or translucent, and becomes illuminated during activation orchanges colors according to different modes of operation for thehandpiece 62.

[0060]FIG. 7a is a partial cross-sectional view of an embodiment of thering switch 60 a (taken at line C-C of FIG. 6) for the handpiece 62according to the invention. According to this particular embodiment, thering switch 60 a, on the outside of the housing 63 of the handpiece 62,sits on top of two sensors 61A and 61B. As pressure 70A is applied tothe ring 60 a in one direction, sensor 61A detects that pressure andstarts a mode of operation, e.g., activate the handpiece 62. As pressure70B is applied to the ring 60 a in the opposing direction, sensor 61Bdetects that pressure and starts a corresponding mode of operation,e.g., deactivate the handpiece 62, or proportionally reduces the powerby which the handpiece 62 is operating, depending on the amount ofpressure applied.

[0061]FIG. 7b is a partial cross-sectional view of another embodiment ofthe ring switch 60 a (taken at line C-C of FIG. 6) for the handpiece 62according to the invention. According to this particular embodiment, thering switch 60 a itself is the sensor which comprises a piezo portion 64and a substrate 65 made of suitably deformable, flexible material. Whenpressure 70B is applied against the piezo portion 64, the ring switch 60a generates an output voltage proportional to the force applied(pressure 70B) and the direction of that applied force, and results in apolarity signal. The substrate 65 adds strength to the ring switch 60 a.When pressure 70A is applied against the substrate 65 in the otherdirection, the ring switch 60 a generates an opposing or differentpolarity signal than the polarity signal resulting from pressure 70B,thereby permitting at least two modes of operation (such as cutting orcoagulation) from a single ring/sensor.

[0062]FIG. 7c is a partial cross-sectional view of yet anotherembodiment of the ring switch 60 a (taken at C-C of FIG. 6) for thehandpiece 62 according to the invention. According to this particularembodiment, the ring switch 60 a includes a capacitance transducercomprising, a center ring 67, which is made of a conductive materialsuch as a relatively inflexible metal, an outer layer of insulative ring66 made of foam or elastomer, a conductive ring 65 which is an electrodemade of a relatively flexible metal, another outer layer of insulativering 68 also made of foam or elastomer on the other side of center ring67, and another conductive ring 69 which is an electrode with anopposite polarity also made of a relatively flexible metal. Whenpressure 70A is applied to one side of the ring switch 60 a, theinsulative ring 66 is deflected and the foam or elastomer is depressed,which brings the conductive ring 65 closer to the center ring 67 andthereby reduces the capacitance in proportion to the pressure 70A asapplied. The change in the capacitance between the conductive ring 65and the center ring 67 activates the handpiece, causes the handpiece 62to run in a specific mode of operation (such as cutting or coagulation),or proportionally increases the speed of operation depending on theamount of pressure 70A as applied. Conversely, when pressure 70B isapplied to the other side of the ring switch 60 a, the insulative ring68 is deflected and the foam or elastomer is depressed, which brings theconductive ring 69 closer to the center ring 67 and thereby reduces thecapacitance in proportion to the pressure 70B as applied. The change inthe capacitance between the conductive ring 69 and the center ring 67deactivates the handpiece, causes the handpiece 62 to run in acorresponding mode of operation (such as cutting or coagulation), orproportionally reduces the speed of operation depending on the amount ofpressure 70B as applied.

[0063]FIG. 7d is a partial cross-sectional view of a further embodimentof the ring switch 60 a (taken at C-C of FIG. 6) for the handpiece 62according to the invention. According to this particular embodiment, thering switch 60 a includes a center ring 73, which is made of aconductive material such as a relatively rigid metal, a pointer ring 72which is relatively flexible, compressible and deformable (such as afoam or elastomer), a conductive ring 71 which is an electrode made of arelatively flexible metal, another pointer ring 74 which is relativelyflexible, compressible and deformable (such as a foam or elastomer), andanother conductive ring 75 which is an electrode with an oppositepolarity, also made of a relatively flexible metal. When pressure 70A isapplied to one side of the ring switch 60 a, the tip of the pointer ring72 is flattened against the rigid center ring 73 which decreases thespace between the conductive ring 71 and the center ring 73 and therebyreduces the capacitance in proportion to the pressure 70A as applied.The change in the capacitance between the conductive ring 71 and thecenter ring 73 activates the handpiece 62, causes the handpiece 62 torun in a specific mode of operation (such as cutting or coagulation), orproportionally increases the power or speed of operation depending onthe amount of pressure 70A as applied. Conversely, when pressure 70B isapplied to the other side of the ring switch 60 a, the tip of thepointer ring 74 is flattened against the rigid center ring 73 whichdecreases the space between the conductive ring 75 and the center ring73 and thereby reduces the capacitance in proportion to the pressure 70Bas applied. The change in the capacitance between the conductive ring 75and the center ring 73 activates the handpiece 62, causes the handpiece62 to run in a specific mode of operation (such as cutting orcoagulation), or proportionally decreases the power or speed ofoperation depending on the amount of pressure 70B as applied.

[0064]FIGS. 7e and 7 f are partial cross sectional views of two otherembodiments of the ring switch 60 a (taken at B-B of FIG. 6) for thehandpiece 62 according to the invention. The ring switch 60 a itself isa sensor which comprises a center ring 76 which is made of a relativelyrigid material, and two piezo rings 76A (or 77A which is a smallerversion of piezo ring 76A) and 76B (or 77B which is a smaller version ofpiezo ring 76B). When pressure 70A is directly applied against thecenter ring 76 and indirectly against the piezo ring 76B (or 77B), thering switch 60 a generates an output voltage proportional to the forceapplied (pressure 70A) and results in a polarity signal, therebyactivating the handpiece 62, causing the handpiece 62 to run in aspecific mode of operation (such as cutting or coagulation), orproportionally increasing the power or speed of operation depending onthe amount of pressure 70A as applied. Conversely, when pressure 70B isdirectly applied against the center ring 76 and indirectly against thepiezo ring 76A (or 77A), the ring switch 60 a generates an outputvoltage proportional to the force applied (pressure 70B) and results ina different or opposing polarity signal, thereby activating thehandpiece 62, causing the handpiece 62 to run in a specific mode ofoperation (such as cutting or coagulation), or proportionally decreasingthe power or speed of operation depending on the amount of pressure 70Bas applied. This permits at least two modes of operation (such ascutting or coagulation) from a single ring/sensor 60 a.

[0065]FIG. 7g is a partial cross-sectional view of yet anotherembodiment of the ring switch 60 a (taken at C-C of FIG. 6) for thehandpiece 62 according to the invention. According to this particularembodiment, the ring switch 60 a includes a single piezo ring 78 withflexible seals 78A and 78B (made of, e.g., elastomer). When pressure 70Ais applied against the piezo ring 78, the ring switch 60 a generates anoutput voltage proportional to the force applied (pressure 70A) andresults in a polarity signal, thereby activating the handpiece 62,causing the handpiece 62 to run in a specific mode of operation (such ascutting or coagulation), or proportionally increasing the power or speedof operation depending on the amount of pressure 70A as applied.Conversely, when pressure 70B is applied against the piezo ring 78, thering switch 60 a generates an output voltage proportional to the forceapplied (pressure 70B) and results in an opposing polarity signal,thereby activating the handpiece 62, causing the handpiece 62 to run ina specific mode of operation (such as cutting or coagulation), orproportionally decreasing the power or speed of operation depending onthe amount of pressure 70B as applied. In addition, a protectiveexternal cover made of elastomer (not shown) may be placed over the ringswitch 60 a to protect against environmental and impact damage, as inthis particular embodiment and other embodiments described herein.

[0066]FIG. 7h is a partial cross-sectional view of an additionalembodiment of the ring switch 60 a (taken at C-C of FIG. 6) for thehandpiece 62 according to the invention. According to this particularembodiment, the ring switch 60 a includes a center ring 700 which isrelatively rigid with two adjacent seals 701 and 702 which arerelatively flexible for supporting the center ring 700. Inside thehandpiece housing 63, a piezo ring 705 is adhesively attached to thebottom 703 of the center ring 700 with a piezo support ring 704 forsupporting the piezo ring 705. When pressure 70A is directly appliedagainst the center ring 700 and indirectly against the piezo ring 705,the ring switch 60 a generates an output voltage proportional to theforce applied (pressure 70A) and results in a polarity signal, therebyactivating the handpiece 62, causing the handpiece 62 to run in aspecific mode of operation (such as cutting or coagulation), orproportionally increasing the power or speed of operation depending onthe amount of pressure 70A as applied. Conversely, when pressure 70B isdirectly applied against the center ring 700 and indirectly against thepiezo ring 705 in the opposite direction, the ring switch 60 a generatesan output voltage proportional to the force applied (pressure 70B) andresults in a different or opposing polarity signal, thereby activatingthe handpiece 62, causing the handpiece 62 to run in a specific mode ofoperation (such as cutting or coagulation), or proportionally decreasingthe power or speed of operation depending on the amount of pressure 70Bas applied. Moreover, the center ring 700 can be segmented into two orthree sections to particularly localize the pressure applied (70A or70B) to the corresponding segment of the piezo ring 705. As describedherein and above, the piezo ring 705 can also be an integral part of thecenter ring 700.

[0067]FIG. 7i is a partial cross sectional view of yet anotherembodiment of the ring switch 60 a (taken at C-C of FIG. 6) for thehandpiece 62 according to the invention. According to this particularembodiment, the ring switch 60 a includes a center ring 710 made ofrelatively flexible material, such as foam or elastomer, with two outerrings 713 and 714 which are relatively rigid or semi-rigid, and tworelatively flexible rings 711 and 712 for supporting the center ring 710with the outer rings 713 and 714. Inside the handpiece housing 63, twopiezo rings 715A and 715B are fixed to the two sides of the bottom ofthe center ring 710 with the outer rings 713 and 714. The two piezorings 715A and 715B are continuously or periodically monitored, i.e.,stimulated using AC (alternating current) power near or generally closeto the resonant frequency, for avoiding cross talk between the two piezorings 715A and 715B. The resonant frequency or amount of energy neededto maintain a given displacement is monitored. As pressure (70A or 70B)is applied to the center ring 710, these characteristics change (e.g.,the resonant frequency and displacement), and that change is the basisfor controlling the mode of operation of the handpiece 62.Alternatively, the pulse, amplitude, echo and timing of the response ofthe two piezo rings 715A and 715B as a result of the pressure applied(70A and 70B) are monitored, and subsequent Fast Fourier Transform (FFT)analysis can be performed.

[0068] When pressure 70A is directly applied against the center ring 710and indirectly against the piezo rings 715A and 715B, the ring switch 60a generates an output voltage proportional to the force applied(pressure 70A) and results in a polarity signal, thereby activating,causing the handpiece 62 to run in a specific mode of operation (such ascutting or coagulation), or proportionally increasing the speed ofoperation depending on the amount of pressure 70A as applied.Conversely, when pressure 70B is directly applied against the centerring 710 and indirectly against the piezo rings 715A and 715B in theopposite direction, the ring switch 60 a generates an output voltageproportional to the force applied (pressure 70B) and results in adifferent or opposing polarity signal, thereby activating the handpiece62, causing the handpiece 62 to run in a specific mode of operation(such as cutting or coagulation), or proportionally decreasing the poweror speed of operation depending on the amount of pressure 70B asapplied.

[0069] In the alternative, when pressure 70A is applied to one side ofthe ring switch 60 a, the piezo ring 715A is deflected, resulting in avibration being picked up by the other piezo ring 715B. The center ring710 which is made of elastomer, is depressed. This increases thevibration transmission to the piezo ring 715B. That change in thevibration transmission activates the handpiece 62, causes the handpiece62 to run in a specific mode of operation (such as cutting orcoagulation), or proportionally increases power or the speed ofoperation depending on the amount of pressure 70A as applied.Conversely, when pressure 70B is applied to the other side of the ringswitch 60 a, the piezo ring 715B is deflected, resulting in a vibrationbeing picked up by the piezo ring 715A. The center ring 710 isdepressed, which increases the vibration transmission to the piezo ring715A. That change in the vibration transmission deactivates thehandpiece 62, causes the handpiece 62 to run in a specific mode ofoperation (such as cutting or coagulation), or proportionally decreasespower or the speed of operation depending on the amount of pressure 70Bas applied.

[0070]FIGS. 8 and 8a are diagrams that respectively illustrate anembodiment and prototype for the ring switch 60 a with activation zones81A and 81B for the handpiece 62 according to the invention. A harmonicgenerator 510, illustrated in FIG. 2, provides electrical energy to thehandpiece 62, which imparts ultrasonic longitudinal movement to asurgical device, such as a sharp scalpel blade 603 used for dissectionor coagulation. The handpiece 62 is connected to the harmonic generator510 by a coaxial cable 526. The ring switch 60 a is a ring-likecircumferential appendage on the handpiece 62, including the supportring 81 and two adjacent activation zones 81A and 81B, located near thedistal end thereof. The human operators of the handpiece 62 can presstheir fingers against the surface of the activation zones (81A or 81B)and the finger pressure or force, which can be either perpendicular ornon-perpendicular to the surface of the handpiece 62, is sensed andconverted into an activation signal. The activation zones 81A and 81Bare circumferential bands for sensing pressure for activating anddeactivating the handpiece 62, changing the speed thereof (e.g., full orvariable power), or running the handpiece 62 in specific modes ofoperation (e.g., cutting or coagulation). The support ring 81 provides atactile reference point for a human operator of the handpiece 62relative to the activation zones 81A and 81B. The support ring 81 alsoprovides finger support for the human operator that reduces inadvertentactivation due to unwanted grasping contact with the activation zones81A and 81B. Furthermore, the support ring 81 can be transparent ortranslucent for indicating the activation status and mode of operationof the handpiece 62 by becoming illuminated during activation orchanging colors according to the current mode of operation.

[0071] The activation zones 81A, 81B can include, but are not limitedto, (a) force sensitive resistors whose resistance is proportional tothe force or pressure applied; (b) force sensitive capacitors whosecapacitance is proportional to the pressure, deflection, or compressionof the insulation layer between the two electrodes therein or isproportional to the spacing between the two conductive layers therein;(c) strain gauges mounted underneath or integral with the handpiecehousing such that the pressure applied thereto results in an outputchange of the strain gauges; (d) magnet(s) encased in or resting in anelastomer with a sensor inside the handpiece that detects the fieldstrength of the magnet(s) and monitor changes relative to the forceapplied or the gap change therein; and (e) piezo film or piezo ceramicelements whose charge or voltage is proportional to the force orpressure applied thereto.

[0072]FIGS. 9 and 9a are diagrams that respectively illustrate anotherembodiment of the ring switch 60 a with segmented activation zones 82Aand 82B for the handpiece 62 according to the invention. A harmonicgenerator 510, illustrated in FIG. 2, provides electrical energy to thehandpiece 62 which imparts ultrasonic longitudinal movement to asurgical device such as the sharp scalpel blade 603 used for dissectionor coagulation. The handpiece 62 is connected to the harmonic generator510 by the coaxial cable 526. The ring switch 60 a is a ring-likecircumferential appendage on the handpiece 62, which is segmented intotwo adjacent activation zones 82A and 82B, located near the distal endthereof. The ring 60 a is segmented so that action or pressure from oneside of the ring (82A) is isolated from the other side of the ring(82B). The segmented activation zones 82A and 82B are for sensingpressure for activating and deactivating the handpiece 62, changing thespeed thereof (e.g., full or variable power), or running the handpiece62 in specific modes of operation (e.g., cutting or coagulation). Forinstance, as pressure 70A is applied in one direction against the ringswitch 60 a, one mode of operation is activated, e.g., cutting orvariable power, for the handpiece 62. As pressure 70B is applied in theopposite direction against the ring switch 60 a, another mode ofoperation is activated, e.g., coagulation or full power, for thehandpiece 62. The ring 60 a itself is a tactile reference point for ahuman operator of the handpiece 62 relative to the segmented activationzones 82A and 82B. The ring 60 a also provides finger support for thehuman operator that reduces inadvertent activation due to unwantedgrasping contact with the segmented activation zones 82A and 82B.Furthermore, when pressure 70C is applied to the ring 60 a in theperpendicular direction, an additional mode of operation is activated.Moreover, the ring 60 a or the segmented activation zones (82A or 82B)can be transparent or translucent for indicating the activation statusand mode of operation of the handpiece 62 by becoming illuminated duringactivation or changing colors according to the current mode ofoperation.

[0073]FIGS. 10 and 10a are diagrams that respectively illustrate yetanother embodiment and prototype for the ring switch 60 a withactivation zones 83A and 83B for the handpiece 62 according to theinvention. The harmonic generator 510, illustrated in FIG. 2, provideselectrical energy to the handpiece 62 which imparts ultrasoniclongitudinal movement to the surgical device 603 used for dissection orcoagulation. The handpiece 62 is connected to the harmonic generator 510by the coaxial cable 526. The ring switch 60 a is a ring-likecircumferential appendage on the handpiece 62, including the distal rib84, a proximal rib 85, and two adjacent activation zones 83A and 83Btherebetween, all located near the distal end of the handpiece 62. Humanoperators of the handpiece 62 can press their fingers against thesurface of the activation zones (83A or 83B) and the finger pressure orforce, which can be either perpendicular or non-perpendicular to thesurface of the handpiece 62, is sensed and converted into an activationsignal. The activation zones 83A and 83B are circumferential bands forsensing pressure for activating and deactivating the handpiece 62,changing the speed thereof (e.g., full or variable power), or runningthe handpiece 62 in specific modes of operation (e.g., cutting orcoagulation). The distal rib 84 and the proximal rib 85 provide atactile reference point for a human operator of the handpiece 62relative to the activation zones 83A and 83B. The distal rib 84 and theproximal rib 85 are tapered to guide the fingers of the human operatorof the handpiece 62 into the activation zones 83A and 83B. The distalrib 84 and the proximal rib 85 also provide finger support for the humanoperator that reduces inadvertent activation due to unwanted graspingcontact with the activation zones 83A and 83B. Furthermore, the distalrib 84 or the proximal rib 85 can be transparent or translucent forindicating the activation status and mode of operation of the handpiece62 by becoming illuminated during activation or changing colorsaccording to the current mode of operation.

[0074] In addition, the ring switch 60 a can also include a middle rib86, as shown in FIG. 10b, which serves as a divider between activationzones 83A and 83B. The middle rib 86 provides a means for grasping thehandpiece 62 in the activation zones without creating undue activationpressure, since the fingers of the human operator bridge across theactivation zones 83A and 83B as a result of the addition of the middlerib 86. The middle rib 86 is shaped differently than the distal rib 84and the proximal rib 85, which provides additional tactile referencefeedback for giving the human operator of the handpiece 62 a feel offinger location relative to the active zones 83A and 83B.

[0075]FIG. 11 is a diagram that illustrates a further embodiment of thering switch 60 a with activation zones 87A and 87B for the handpiece 62according to the invention. A harmonic generator 510, illustrated inFIG. 2, provides electrical energy to the handpiece 62 which impartsultrasonic longitudinal movement to a surgical device such as a sharpscalpel blade 603 used for dissection or coagulation. The handpiece 62is connected to the harmonic generator 510 by a coaxial cable 526. Thering switch 60 a is a ring-like circumferential appendage on thehandpiece 62, including two activation zones 87A and 87B with a divider88 which is a recess or protrusion. The human operator of the handpiece62 can press their fingers against the surface of the activation zones(87A or 87B) and the finger pressure or force, which can be eitherperpendicular or non-perpendicular to the surface of the handpiece 62,is sensed and converted into an activation signal. The activation zones83A and 83B are circumferential bands for sensing pressure foractivating and deactivating the handpiece 62, changing the speed thereof(e.g., full or variable power), or running the handpiece 62 in specificmodes of operation (e.g., cutting or coagulation). The divider 88provides a tactile reference point for a human operator of the handpiece62 relative to the activation zones 87A and 87B. Furthermore, thedivider 88 can be transparent or translucent for indicating theactivation status and mode of operation of the handpiece 62 by becomingilluminated during activation or changing colors according to thecurrent mode of operation.

[0076]FIG. 12 is a diagram that illustrate an additional embodiment ofthe ring switch 60 a with activation zones and sub-zones for thehandpiece 62 according to the invention. A harmonic generator 510,illustrated in FIG. 2, provides electrical energy to the handpiece 62which imparts ultrasonic longitudinal movement to a surgical device suchas a sharp scalpel blade 603 used for dissection or coagulation. Thehandpiece 62 is connected to the harmonic generator 510 by a coaxialcable 526. The ring switch 60 a is a ring-like circumferential appendageon the handpiece 62, including a sliding barrier 90 and two activationzones 91 and 92 which are tape-like sensors that conform on thehandpiece 62. A human operator of the handpiece 62 can press theirfingers against the surface activation zones (91 or 92) and this force,which is generally perpendicular to the surface of the handpiecehousing, is sensed and converted into an activation signal foractivating and deactivating the handpiece 62, or running it in variousmodes of operations (e.g., cutting or coagulation). The activation zones91 and 92 are further divided into two groups of sub-zones (91A, 91B,91C) and (92A, 92B, 92C), respectively, which, when pressed upon,activate additional modes of operation for the handpiece 62, e.g.,variable power levels. The sliding barrier 90 wraps around the handpiece62 and covers a portion of the activation zones 91 and 92, and moreparticularly, sub-zones 91A and 92A. The sliding barrier 90 shieldssub-zones 91A and 92A to prevent activation, or to attenuate thepressure reaching the particular sub-zone. The sliding barrier 90 can beremovably attached to the handpiece 62 which is snapped onto a desiredposition (e.g., over a particular sub-zone) if needed. The sub-zonesallow flexibility of use of the handpiece 62 by providing specific,adaptable configurations of active zones and non-activation fingersupporting zones (e.g., 91A and 92A) according to the preferences of thehuman operator of the handpiece. In addition, the sub-zones can beuniquely colored or numbered or otherwise marked for readyidentification by the human operator.

[0077] The electromechanical switch for the handpiece described hereincan be any type, including a conventional mechanical lever contactswitch, including, e.g., a stationary contact and a flexible contact.For such a switch, the flexible conductive arm is depressed which makescontact with the stationary contact. An exemplary switch includes aberyllium copper arm that is depressed to make contact with a berylliumcopper pad, thereby making contact and completing the switch circuit.The electromechanical switch for the handpiece according to theinvention can also be a carbon button switch, such as a rubber buttonthat includes a carbon pad attached to the underside of the button. Whenthe button is depressed, the carbon pad descends upon a pair ofstationary contacts, such as two gold-plated pads on a printed circuitboard. The carbon pad rests against and electrically bridges the goldplated pads, thereby making contact and completing the switch circuit.In a further embodiment, the carbon pad can be replaced with a metallicpad such as a gold-plated copper pad.

[0078] Although the invention has been particularly shown and describedin detail with reference to the preferred embodiments thereof, theembodiments are not intended to be exhaustive or to limit the inventionto the precise forms disclosed herein. It will be understood by thoseskilled in the art that many modifications in form and detail may bemade without departing from the spirit and scope of the invention.Similarly, any process steps described herein may be interchangeablewith other steps to achieve substantially the same result. All suchmodifications are intended to be encompassed within the scope of theinvention, which is defined by the following claims and theirequivalents.

We claim:
 1. A system for implementing surgical procedures comprising:an ultrasonic surgical handpiece having an end-effector; a generatorconsole for controlling the handpiece; an electrical connectionconnecting the handpiece and the console, wherein the console sends adrive current to drive the handpiece which imparts ultrasoniclongitudinal movement to the end-effector; and a finger-operated switchprovided on a housing of the handpiece, the switch activating thehandpiece at a first power level if a monitored pressure on the switchreaches a high threshold, and deactivating the handpiece if themonitored pressure reaches a low threshold.
 2. The system of claim 1wherein the switch is distally located on the handpiece.
 3. The systemof claim 1 wherein the handpiece is operated at a power level selectedfrom a plurality of power levels if the monitored pressure reaches aspecific threshold of a respective plurality of thresholds correspondingto the plurality of power levels.
 4. The system of claim 1 wherein thepressure is monitored by a sensor located inside the housing of thehandpiece selected from a group consisting of an electromechanicalswitch, a force-sensitive resistor, force sensitive capacitor, straingauge, magnet, ferromagnet, piezo film and piezo ceramic.
 5. The systemof claim 1 wherein the switch comprises a pair of switch button members.6. The system of claim 1 wherein the switch further comprises aninactive center region for resting of a finger and serving as a tactilereference.
 7. The system of claim 1 wherein the switch is generallyuser-alignable with the end-effector.
 8. The system of claim 1 whereinthe switch is symmetrically aligned and indexed to the end-effector. 9.The system of claim 5 wherein each of the switch button memberscomprises: an upper surface and a lower surface; a first post and asecond post extending outwardly away from the lower surface; and a firstraised section and a second raised section on the upper surface, saidraised section being supported by a center recessed section formedtherebetween.
 10. The system of claim 9 wherein the first post isdisposed generally opposite the first raised section and the second postis disposed generally opposite the second raised section so that thefirst post is directed toward the interior of the handpiece when thefirst raised section is depressed and the second post is directed towardthe interior of the handpiece when the second raised section isdepressed.
 11. The system of claim 1 wherein the switch is a ring switchwith a ring-like circumferential appendage on the handpiece that islocated near a distal end of the handpiece.
 12. The system of claim 11wherein the ring switch comprises a capacitive transducer having acenter ring, an outer layer of elastomer on the exterior of the centerring, and a ring electrode on top of the ring switch.
 13. The system ofclaim 11 further including multicolor illumination and a control suchthat the ring switch becomes illuminated in difference colorscorresponding a plurality of pressure thresholds.
 14. The system ofclaim 11 wherein the ring switch is a sensor comprising a piezo portionand a substrate adjacently disposed with the piezo portion, the ringswitch outputting a first polarity signal when pressure is applied tothe piezo portion and outputting a second opposing polarity signal whenpressure is applied to the substrate.
 15. The system of claim 11 whereinthe ring switch is a sensor comprising a first piezo ring, a secondpiezo ring, and a center ring disposed between the first piezo ring andthe second piezo ring, the ring switch outputting a first polaritysignal when pressure is applied to the first piezo ring and outputting asecond opposing polarity signal when pressure is applied to the secondpiezo ring.
 16. The system of claim 11 wherein the ring switch comprisesa first seal and a second seal, and a piezo ring disposed between thefirst seal and the second seal, the ring switch outputting a firstpolarity signal when pressure is applied in one direction to the piezoring and outputting a second opposing polarity signal when pressure isapplied in another direction to the piezo ring.
 17. The system of claim11 wherein the ring switch comprises a pair of outer rings, a centerring disposed between the outer rings, and a pair of flexible ringsrespectfully located on the exterior of the outer rings to support thecenter ring with the outer rings, and a pair of piezo rings fixed to twosides of bottom of the center ring.
 18. The system of claim 11 whereinthe ring switch comprises a support ring and a pair of adjacentlylocated activation zones which are circumferential bands seriallyconnected with the support ring.
 19. The system of claim 18 wherein theactivation zones consist of one of an electromechanical switch, forcesensitive resistors, force sensitive capacitors, strain gauges, magnets,and piezo material.
 20. The system of claim 18 wherein the ring switchfurther comprises a middle rib disposed between the activation zones,the middle rib serving as a divider for the activation zones.
 21. Thesystem of claim 20 further including multicolor illumination and acontrol so that the middle rib becomes illuminated in difference colorscorresponding to a plurality of pressure thresholds.
 22. The system ofclaim 18 wherein the ring switch further comprises a distal rib locatedon a distal end of the activation zones.
 23. The system of claim 22further including multicolor illumination and a control so that thedistal rib becomes illuminated in difference colors corresponding to aplurality of thresholds.
 24. The system of claim 18 wherein the ringswitch further comprises a proximal rib on a proximal end of theactivation zones.
 25. The system of claim 24 further includingmulticolor illumination and a control so that the proximal rib becomesilluminated in difference colors corresponding to a plurality ofthresholds.
 26. The system of claim 18 wherein each of the activationzones is further divided into subzones corresponding to variable powerlevels of the plurality of pressure thresholds.
 27. The system of claim1 further comprising switches on opposing sides of the handpiece thatgenerally avoid inadvertent activation.
 28. The system of claim 1wherein the switch is a hysteresis switch.
 29. The system of claim 11wherein the ring switch further comprises a sliding barrier covering aportion of the circumferential appendage.
 30. The system of claim 1wherein the switch provides its switching functionality according to alagging effect as the monitored pressured on the switch is changed. 31.A system for implementing surgical procedures comprising: an ultrasonicsurgical handpiece having an end-effector; a generator console forcontrolling the handpiece; an electrical connection connecting thehandpiece and the console, wherein the console sends a drive current todrive the handpiece which imparts ultrasonic longitudinal movement tothe end-effector; and a finger-operated switch provided on a housing ofthe handpiece, the switch activating the handpiece at a first powerlevel and deactivating the handpiece if a low threshold is reached. 32.The system of claim 31 wherein the switch is distally located on thehandpiece.
 33. The system of claim 31 wherein the switch furthercomprises a sensor located inside the housing of the handpiece selectedfrom a group consisting of an electromechanical switch, aforce-sensitive resistor, force sensitive capacitor, strain gauge,magnet, ferromagnet, piezo film and piezo ceramic.
 34. The system ofclaim 31 wherein the switch comprises a pair of switch button members.35. The system of claim 31 wherein the switch further comprises aninactive center region for resting of a finger and serving as a tactilereference.
 36. The system of claim 31 wherein the switch is generallyuser-alignable with the end-effector.
 37. The system of claim 31 whereinthe switch is symmetrically aligned and indexed to the end-effector. 38.The system of claim 34 wherein each of the switch button memberscomprises: an upper surface and a lower surface; a first post and asecond post extending outwardly away from the lower surface; and a firstraised section and a second raised section on the upper surface, saidraised section being supported by a center recessed section formedtherebetween.
 39. The system of claim 38 wherein the first post isdisposed generally opposite the first raised section and the second postis disposed generally opposite the second raised section so that thefirst post is directed toward the interior of the handpiece when thefirst raised section is depressed and the second post is directed towardthe interior of the handpiece when the second raised section isdepressed.
 40. The system of claim 31 wherein the switch activates thehandpiece at the first power level if a monitored pressure on the switchreaches a high threshold, and deactivating the handpiece if themonitored pressure reaches the low threshold.
 41. The system of claim 40wherein the switch is a ring switch with a ring-like circumferentialappendage on the handpiece that is located near a distal end of thehandpiece.
 42. The system of claim 41 wherein the ring switch comprisesa capacitive transducer having a center ring, an outer layer ofelastomer on the exterior of the center ring, and a ring electrode ontop of the ring switch.
 43. The system of claim 41 further includingmulticolor illumination and a control such that the ring switch becomesilluminated in difference colors corresponding to a plurality ofpressure thresholds.
 44. The system of claim 41 wherein the ring switchis a sensor comprising a piezo portion and a substrate adjacentlydisposed with the piezo portion, the ring switch outputting a firstpolarity signal when pressure is applied to the piezo portion andoutputting a second opposing polarity signal when pressure is applied tothe substrate.
 45. The system of claim 41 wherein the ring switch is asensor comprising a first piezo ring, a second piezo ring, and a centerring disposed between the first piezo ring and the second piezo ring,the ring switch outputting a first polarity signal when pressure isapplied to the first piezo ring and outputting a second opposingpolarity signal when pressure is applied to the second piezo ring. 46.The system of claim 41 wherein the ring switch comprises a first sealand a second seal, and a piezo ring disposed between the first seal andthe second seal, the ring switch outputting a first polarity signal whenpressure is applied in one direction to the piezo ring and outputting asecond opposing polarity signal when pressure is applied in anotherdirection to the piezo ring.
 47. The system of claim 41 wherein the ringswitch comprises a pair of outer rings, a center ring disposed betweenthe outer rings, and a pair of flexible rings respectfully located onthe exterior of the outer rings to support the center ring with theouter rings, and a pair of piezo rings fixed to two sides of bottom ofthe center ring.
 48. The system of claim 41 wherein the ring switchcomprises a support ring and a pair of adjacently located activationzones which are circumferential bands serially connected with thesupport ring.
 49. The system of claim 48 wherein the activation zonesconsist of one of an electro-mechanical switch, force sensitiveresistors, force sensitive capacitors, strain gauges, magnets, and piezomaterial.
 50. The system of claim 48 wherein the ring switch furthercomprises a middle rib disposed between the activation zones, the middlerib serving as a divider for the activation zones.
 51. The system ofclaim 50 further including multicolor illumination and a control so thatthe middle rib becomes illuminated in difference colors corresponding toa plurality of pressure thresholds.
 52. The system of claim 48 whereinthe ring switch further comprises a distal rib located on a distal endof the activation zones.
 53. The system of claim 52 further includingmulticolor illumination and a control so that the distal rib becomesilluminated in difference colors corresponding to a plurality ofthresholds.
 54. The system of claim 48 wherein the ring switch furthercomprises a proximal rib on a proximal end of the activation zones. 55.The system of claim 54 further including multicolor illumination and acontrol so that the proximal rib becomes illuminated in differencecolors corresponding to a plurality of thresholds.
 56. The system ofclaim 48 wherein each of the activation zones is further divided intosubzones corresponding to variable power levels of the plurality ofpressure thresholds.
 57. The system of claim 31 further comprisingswitches on opposing sides of the handpiece that generally avoidinadvertent activation.
 58. The system of claim 31 wherein the switch isa hysteresis switch.
 59. The system of claim 41 wherein the ring switchfurther comprises a sliding barrier covering a portion of thecircumferential appendage.
 60. The system of claim 48 wherein the ringswitch further comprises a sliding barrier covering at least one of theactivation zones.
 61. A method for controlling an ultrasonic surgicalhandpiece using a switch located on a housing of the handpiece,comprising the steps of: monitoring pressure applied to the housingusing the switch; activating the handpiece at a first power level if themonitored pressure reaches a high threshold; and deactivating thehandpiece if the monitored pressure reaches a low threshold.
 62. Themethod of claim 61 further comprising the step of operating thehandpiece at a power level selected from a plurality of power levels ifthe monitored pressure reaches a specific threshold of a respectiveplurality of thresholds corresponding to the plurality of power levels.63. The method of claim 61 wherein the pressure is monitored by a sensorlocated inside the housing of the handpiece selected from a groupconsisting of an electromechanical switch, a force-sensitive resistor,force sensitive capacitor, strain gauge, magnet, ferromagnet, piezo filmand piezo ceramic.
 64. The method of claim 61 wherein the switch isgenerally aligned with the blade as the blade is rotated.
 65. The methodof claim 61 wherein the switch provides its switching functionalityaccording to a lagging effect as the monitored pressured is changed. 66.An ultrasonic surgical handpiece having a housing with a finger-operatedswitch located thereon, the switch having a sensor for monitoringpressure thereon so that the handpiece is placed in an operative modewhen the sensor monitors a pressure above a first threshold and isplaced in an inoperative mode when the pressure is below a secondthreshold.
 67. The handpiece of claim 66 wherein the first and secondthresholds are the same.
 68. The handpiece of claim 66 wherein the firstthreshold is at a higher pressure than the second threshold.